The eerie fog is thick enough to obscure visibility beyond a range of 500 feet. Creatures viewed from more than 100 feet away are concealed. In addition, the mist distorts peripheral vision, causing one to periodically notice strange shapes moving and shifting about at the limits of their vision. All Perception checks attempted within mirage mist suffer a –1 status penalty as a result, and all DCs for Survival checks to Sense Direction are increased by 5.